The Internet is a web woven of documents written in a hypertext markup language called HTML. Individual web pages are linked to each other via special pointers, so-called “hyperlinks”. The HTML encoding behind such a link is an URL (uniform resource locator) pointing to another HTML document or to another resource providing content such as a picture, a video file, an executable file, a text file or any other kind of digital content. However, browsing the Internet with a browser (e.g. Firefox, Internet Explorer, Opera and the like) may threaten the security of a user's computer system. A URL may point to executable content containing viruses or Trojan horses. Links contained in e-mails mimicking an authentic link of a trusted provider may actually point to Internet sites comprising executable code for phishing passwords and other kinds of sensitive data.
A commonly used approach to secure web browsing is to modify the browser settings as to disable various scripting languages such as flash, active X, JavaScript and the like. However, said solutions often severely limit the kind of content which can be displayed in a web browser. In particular web pages comprising dynamic multimedia content may not be displayed properly or may not be displayed at all in such a browser. Another solution known in the art is to browse the Internet only after having logged in a computer system with a user account having very limited permissions, in particular with a user account not having the permission to install or deinstall any programs. However, this procedure is considered as highly inconvenient as the user may have to switch between different users very often. Still another solution is to use one computer for surfing the Internet and another one for executing EDV programs and administrative tasks. However, more and more application programs and business workflows require a permanent connection to the Internet and using a computer not being connected to the Internet may therefore not be an option.